The present invention generally relates to syringes for injecting liquid medications from prefilled cartridges, and more particularly to a cartridge receiver having a cutter for preparing a cartridge diaphragm.
Local anesthetic is frequently used to numb tissue in a patient's mouth to reduce pain and discomfort a patient may feel during a dental procedure. Conventionally, a reusable syringe assembly is used to inject the anesthetic or medicine from a cartridge or carpule. The cartridge is a glass cylinder containing a local anesthetic and other ingredients. A diaphragm at one end of the cylinder is held in place by an aluminum band. The opposite end of the cylinder has a moveable piston or stopper. The syringe assembly includes a barrel for receiving the cartridge, a plunger rod slidably received in a proximal end of the barrel for actuating the cartridge, an access needle at a distal end of the barrel for puncturing the diaphragm, and a delivery needle connected to the access needle for delivering anesthetic to the patient. In some cases, the plunger rod includes a harpoon for engaging the piston.
Typically, the diaphragm of the cartridge is swabbed with alcohol before being loaded into a pre-sterilized syringe. As the cartridge is loaded into the syringe, the access needle extending proximally from the distal end of the barrel pierces the cartridge diaphragm so the anesthetic in the cartridge can be dispensed. Once the cartridge is in place, the plunger rod of the syringe pushes the piston of the cartridge toward the diaphragm, forcing anesthetic through the access needle, into the delivery needle, and ultimately into the patient.
To assemble the anesthetic syringe assembly the cartridge is swabbed with alcohol, the sterilized syringe is removed from its container, and the alcohol-swabbed cartridge is loaded in the barrel of the syringe. As the plunger moves distally, it forces the cartridge diaphragm onto the access needle and pushes the cartridge piston distally to force the anesthetic through the access needle, through the delivery needle, and ultimately into the patient. As will be appreciated by those skilled in the art, between each use the syringe must be sterilized, a new delivery needle must be mounted on the syringe, and a new cartridge must be prepared and loaded. This multi-step procedure takes time and is resource and labor intensive. There is a need for a syringe assembly that reduces the time, resources, and labor required to provide anesthetic to a patient.